Jetty



May 7, 1935- s. M. woon 2,000,312

JETTY Filed Jan. 6, 1934 :11i- 1 :3' INVENTOR.

ATTORNEYS.

Patented May 7, 1935 UNITED STATES PATENT OFFICE mr'ry `v Sydney M.Wood. Lake Bluff, lll. Appucauonaanuary e, 1934, smal No. 105.495

6 Claims.

erty'is one which has presented enumerable diili` s culties particularlyalong the shores of the Great Lakes and the shore of the ocean wheregreat property destruction has occurred. An important factor in causinga receding shore line yis the erosive action of the waters forces.Necessarily, this erosive action is most damaging during a period whenthe water level is high. and in view of the fact that statistics showthat high levels occur in regular cycles on the Great Lakes, there isalways a period of transition between a low level and a high levelduring which most property owners are inadequately protected.

Heretofore, it has been attempted to check this erosive action( bybuilding retaining walls which parallel the edge of the hillside. Thereis, however, no wall strong enough to permanently withstand the actionof the waters forces, and this type of protection is therefore efcaciousfor a short time only. A long, gradually sloping beach well suppliedwith sand and gravel, is the best protection against erosive action, asit has the ability to rob a storm of its destructive power, and it is tothe formation of a beach of this type that this invention particularlyrelates.

The principal forces causing erosion on a shore line are contributed toby the air and by the water itself, and the two movements set up by theair are wave action and littoral currents. With a wind blowing directlyat right angles to the shore, denudat'ion of the beach takes place, asthere Y is a surface drift shorewardand an undertow lakeward, which,assisted by the fact that the waves stir up sediment, is able'to conveymaterial from the shore out to deeper water.

The most common condition is when the wind is blowing at an obliqueangle to the shore, and when this is the case the sand and otherparticles held in suspension in the water are caused to travel along theshore line. With this fact in mind, it may be seen that the particlescan'be accumulated by the construction of an obstacle across theirpath,.that is. by the construction of a jetty or groin extending intothe water at right angles to the bank. The formation of a suitable typeof protective beach by this method, however, cannot be accomplished withthe ordinary type of groin, as it is found that while deposits may formon the storm side of the jetty, they will tend to concentrate to providea relatively steep slope adjacent the jetty on this side, and on the leeside objectionable scouring will take place.

It is also found that with most types of jetties, scouring will takeplace at the outer end of the jetty due to the accelerated velocity ofthe littoral currents around said end.

It is, therefore, one of the objects of the present invention to providean improved method of forming protective beaches which results in theformation of a long, gradually sloping beach on both sides of the jetty,and in the elimination of lscouring action at the outer end.

A further object of the invention is to provide an improved jetty foreffecting commercial exploitation of the above method.

Other objects of the invention are to provide a jetty which greatlyaccelerates the deposit of beach building material, which nullifles thewave action and reduces the energy of littoral currents, and whichcauses the deposit of a greater percentage of iine sand.

A further object of the invention is to provide a jetty adapted toproduce a beach which is advantageous, not only in that it protects theshore line, but also in that it renders the shore unusually suitable forbathing purposes.

In my Patentv #1,928,473, dated September 26, 1933, one type of jettyfor forming a protective beach is shown and described. This type ofjettv is particularly adapted for use along the shore of a lake such asone of the Great Lakes. 'The present invention contemplates a jetty moreparticularly adapted for us'e along the shores of an ocean. In my priorpatent a construction is shown wherein outwardly increasing permeabilityis obtained by the use of loosely laid rock. Rock, how` ever, isunsatisfactory as a general rule for ocean work because of the fact thatthere is no clay footing in the ocean and the rock is likely to bequickly undermined.

It is therefore a particular object of the present invention'to providea jetty construction which will afford outwardly increasing permeability'wherein the jetty is constructed of means capablel of withstanding theconditions to which it is subjected in ocean use.

A more specific object of the invention is to provide a jetty as abovedescribed comprising spaced upright members laid in two parallel rowswith horizontal members supported between the uprights, both thehorizontalv members and the upright members cooperating to produce thedesired outwardly increasing permeability.

With the above and other objects in view the 'invention consists oi. theart of forming protective beaches and all its parts and combinations asset forth in the claims and all equivalents thereof.

In the accompanying drawing illustrating one complete embodiment of thepreferred form of the invention in which the same reference numeralsdesignate the same parts in all of the views:

Fig. 1 is a plan view of the improved jetty;

Fig. 2 is a side elevational view thereof;

Fig. 3 is a plan view on a reduced scale showing a shore line with aplurality of jetties installed;

Fig. 4 is an enlarged vertical sectional viewA taken online 4-4 of Fig.1; and

Fig. 5 is a similar view taken on line 5 5 of Fig. 1.

Referring more particularly to the drawing, the numeral 8 designates ahillside leading down to a beach bordering an ocean or other body ofwater. In cases where there is an artificial barrier such as a retainingwall paralleling the hillside the jetty may be laid in the same relationwith respect thereto as it is with respect to the hillside 8. 'I'henumeral 9 designates the sand beach and the numeral III the water level.

With the present invention in order to obstruct the littoral currents tocause the deposit of particles of sand in proper formation to provide along. gradually sloping beach, one or more of the jetties, designatedgenerally by the numeral I0', may be extended from the hillside or wall8 outwardly into the water at approximately right angles to thehillside. rIn view of the fact that permeability is unimportant on theportion of the beach close to the hillside which is not ordinarilyreached by the water, it is preferred to construct this portion of thejetty in a different manner from the portion which actually extends intothe water.

As shown in Figs. .1, 2 and 4, a plurality of piles or posts Il, whichare preferably constructed of Portland cement but which may also beformed of creosoted yellow pine or other suitable material, `are driveninto the beach in juxtaposition to one another to form a row extendingfrom the hillside 8 to approximately the waters edge. The piles II maybe reinforced and bound together by one or more metal rods I2 extendingtherethrough. At intervals other piles I3 may be driven alongside of therow of piles II as shown in Fig. 4 and rods 14 having threaded ends I5for the reception of nuts IG- may be inserted transversely through eachpair of piles I3 and through the row of piles -II therebetween.' The rowof pilesl II is preferably larger than shown, and it is desirable tohave it about 65% of the total length of the jetty. j

At the end of the row of piles II similar piles I 1 may be driven intothe sand to form two rows.

as indicated in Fig. l, the rows being spaced apart a distanceapproximately equal to the width of one of the piles. The piles I'I arespaced farther apart as they progress out into the water as may be seenfrom an examination of Fig. 2. Also, the majority of the piles of onerow are staggered with respect tothe piles of the other row.

Between the rows of piles I'I are laid in horizontal position aplurality of similar members I8, these members being laid insuperimposed rows with upper rows terminating short of the lower ones asindicated at I9, 20, 2| and 22. Thus the height of the superimposed rowsof members I8 decreases outwardly.

The upper ends of the piles I.1 may be connected together in anysuitable manner, but it is preferred to utilize obliquely extending rods23 which are threaded at their ends at at 24 to receive nuts 25 in thelmanner* shown in Fig. 5. Other rods 28 may be inserted verticallythrough the superimposed rows of members I8.

The piles -I1 and members I8 may also be formed of Portland cement,creosoted yellow pine or other material capable of withstanding theelements.

It is to be noted that in order to provide a firm foundationI for thestructure, that the piles are driven into the sand a distanceapproximately equal to the portion of their length projecting above thesand.

As a result of thisstructure it will be seen that the water can passthrough the sides of the jetty at any point outwardly of the row II butthat its passage is retarded by both the upright piles I'I and thehorizontal members I 8 and that the amount of this retardation decreasesoutwardly due to the combination of thedecreasing height of thehorizontal members andthe wider spacing of the upright members, thisconstruction serving to form an outwardly increasing permeability.

By referring to Fig. 2 it will be seen that the major portion of thelength of the rows of horizontal members projects above the water linebut that the outer end is submerged. This is for the purpose of allowingthe shore currents to pass at reduced speeds through and over thesubmerged end and to caus'e the retardation of currents passing inwardlyor outwardly along the sides to prevent scouring at the ends and alongthe sides.

It is found that the character of the beach may be still furtherimproved by laying a plurality of jetties of the type described inparallel relation to one-another and spaced apart a substantial distanceas indicated in Fig. 3.

Wherev a solid or impermeable jetty has been used, the littoral currentscarrying the sand and other ne particles in suspension are obstructed bythe sides of the jetty, but the velocity of the currents is acceleratedto cause ,a-rather abrupt turning of the flow of the littoral currentsfrom a direction parallel to the shore line to a direction parallel tothe sides of the jetty, the currents therefore flowing around lthe endof the jetty with' accelerated velocity. When the littoral currentsstrike the sides of -an impermeable jetty, there is likely to be amomentary and rather abrupt change in the direction of travel of thecurrents which causes a. deposit in a rather abrupt manner close to theWindward side of the jetty, and inasmuch as this deposit will beconcentrated adjacent the jetty, any beach developed will have an abruptslope and will not be desirable. Furthermore, due to the acceleratedvelocity of the littoral currents as they move around the end of theimpermeable jetty, thene sands are carried with the current, and themajority of the ll adjacent the jetty will be of coarser material. Inaddition, the action of the currents around the end of an impermeablejetty wherein the velocity is greatly accelerated will cause a markedscouring to take place at the outer end of the jetty, and therebydevelop a deep water spot objectionable for bathing purposes.

With the present invention, it is to be noted that the major portion ofthe length of the jetty is increasingly permeable outwardly, and as aresult, while the littoral currents are obstructed in a manner to causethe deposit of sand and other material held in suspension, nevertheless.

due to the permeable nature of the wall, them* 2. A jetty comprising anelongated wall exwater can flow through the spaces so that there is notthe tendency for the currents to move in a direction parallel to thejetty and travel around the outer end with accelerated velocity such asis the case with the jetty of the impermeable type. Thus scouring at theouter end is eliminated.

Furthermore, due to the fact that the currents are slowed down in auniform manner by the permeable jetty and can trickle through, an evendeposit of fine material is encouraged on both sides of the jetty, andthis deposit will gradually build up, not only directly adjacent thesides, but for a substantial distance laterally therefrom to cause theformation of a long, gradually sloping beach composed of fine particlesof sand. With the impermeable type of jetty, the littoral currents whichrush around the outer end and there cause scouring and which then moveinwardly toward the shore on the other side of the jetty, will cause ascou ing on the lee side.

By referring to Fig. 3, it will be seen that with applicants type ofjetty, that when the wind is traveling in an oblique direction towardthe shore, as indicated by the arrow A, that the littoral currentsindicated by the arrows B will flow somewhat in the manner indicated.that is, approximately parallel to the shore. As said currents strikethe permeable jetty, instead o! changing direction and traveling atright angles to the sides ofthe jetty and around the outer end ataccelerated velocity, they will pass through the permeable jetty andthere will only be a slight tendency to direct the currents outwardly.The currents will then continue as indicated, passing approximatelyparallel to the shore between each pair of jetties and through the nextsuccessive jetty. The result will be a gradual slowing down of thelittoral currents to cause a gradual deposit oi' sand and the formationof an ever widening beach composed of fine material, as indicated by thenumeral 9 wherein the angle of the beach is relatively ilat, and whereinthe tendency for the beach to concentrate directly adjacent the sides ofthe jetty, is minimized.

It will further be seen that with the present invention, the area of newland formed will be much greater per foot of jetty than would occur withan ordinary type of construction.

Although only one form of the invention has been shown and described, itis to be understood that various changes and modifications may be made,and that all of such changes are contemplated as may come within thescope of the claims.

What I claim is:

1. A jetty comprising an elongated wall exltending outwardly at an angleto the shore, said wall being formed of parallel rows of spaced uprightmembers, and other members laid horizontally between said rows, thespacing of the upright members increasing outwardly to provide outwardlyincreasing permeability.

tending outwardly at an angle to the shore, said wall being formed ofparallel rows of spaced upright members, and other members laidhorizontally between said rows, the spacing of the uprightmembersincreasing outwardly, and the height of the portion formed by saidhorizontally laid members decreasing outwardly thereby providing incombination with the upright members a jetty of outwardly increasingpermeability to partially obstruct littoral currents and cause a gradualdecrease in the velocity of said currents and the deposit of beachbuilding material.

3. A jetty comprising an elongatedwall extending outwardly at an angleto the shore, said wall being formed of parallel rows of spaced uprightmembers and other elongated members laid horizontally therebetween insuperimposed rows, the spacing of the upright members increasingoutwardly, and the height of the portion formed by said horizontallylaid members decreasing outwardly thereby providing a jetty of outwardlyincreasing permeability to partially obstruct littoral currents andcause a gradual decrease in the velocity of said currents and thedeposit of beach building material.

4. A jetty comprising an elongated wall extending outwardly at an angleto the shore, said wall being formed of parallel rows of spaced uprightmembers and other elongated members laid horizontally therebetweenin-superimposed rows, the spacing of the upright members increasingoutwardly, and upper rows of horizontally laid members being of lesslength than rows therebelow to provide for outwardly decreasing heightwhich together with the increased spacing of the upright members forms ajetty of outwardly increasing permeability to partially obstructlittoral currents and thereby cause a gradual" decrease in the velocityof said ciu'rents and the deposit ofbeach building material.

5. A jetty comprising an elongated wall extending outwardly at an angleto the shore, said wall being formed of parallel rows of spaced uprightmembers, and other members laid horizontally between said rows, thespacing ofthe upright members increasing outwardly to provide outwardlyincreasing permeability and upright members of one row being staggeredwith respect to upright members of the other row.

6. A jetty comprising an elongated wall extend-v ing outwardly at anangle to the shore, said wall being formed of parallel rows o! spacedupright members, and other members laid horizontally between said rows,the spacing of the upright members increasing outwardly to provideoutwardly increasing permeability, and means con- .necting uprightmembers of one row with adiacent upright members oi' the other row.

SYDNEY M. woon.

